How couples in rural sub-Saharan Africa cope with HIV/AIDS is important, difficult to analyze and understudied. Little attention has been paid to rural married couples, even though these are the majority of the population and most are still uninfected. How husbands and wives respond to HIV/AIDS will have substantial impact on the course of the epidemic. The principal aim of this project is to collect and analyze longitudinal quantitative and qualitative social science and biomarker data for random samples in rural Malawi. The new data will improve understanding of two critical questions: (a) how rural married couples are developing strategies of prevention through interactions with their social networks and with each other and how their attitudes and behaviors change and (b) how these strategies, attitudes and behaviors reflect changes in local understandings of gender and in gender-specific networks. The central hypothesis is that rural married couples are responding to HIV/AIDS risks in gendered ways that reflect interactions between husbands and wives and within the gender-specific networks of both husbands and wives. The specific aims are: (1) To create new integrated social science and biomarker longitudinal quantitative and qualitative public-use data for the 1998-2006 period that will support a variety of approaches for addressing our aims; (2) Investigate impacts of interactions both within marital couples and within their conversational networks on their strategies, attitudes and behaviors related to HIV/AIDS and other STIs; (3) To explore the influence of gender on the impacts of social interactions on strategies, attitudes and behaviors related to HIV/AIDS and other STIs. The new data include one new round of qualitative data necessary for describing the formulation of gendered strategies of prevention, and whether and how these strategies are changing; biomarkers necessary for solving problems in the measurement of risk behavior and its change, and new rounds of household survey necessary for solving estimation problems that arise in making causal analyses of change over time when not all the characteristics of husbands, wives and their network partners can be observed and when the choice of spouses and network partners is not random.